Lactose is the sugar found in milk and is in other dairy products. When you are lactose intolerant you cannot digest foods or drinks with lactose in them. Lactase is an enzyme needed for proper metabolization of lactose in human beings. The lactose disaccharide cannot be absorved through the intestinal wall into the bloodstream, so remains in the intestines. When the bacteria adapts to the undigested sugar they switch over to lactose metabolism and this creates gas and unpleasant abdominal symptoms. Lactase breaks down milk and sugar into two simpler forms of sugar called glucose and galactose, and they are absorbed into the bloodstream. Not all people that have symptoms are lactose intolerant.
Molecular Basis Description
The picture on the left explains how glucose and galactose link together. Lactase binds with water to create the linkage. Once it is combined with water the lactase enzymes then move onto the next lactose molecule and this is repeated each time. The body does not need to produce many enzymes because they work efficiently and economically. They do not change after the reaction, they just move to the next lactose molecule. The outcome of this reaction is the formation of glucose and galactose. These monosaccharides are absorbed and ready to be transported in the small intestine.
Major Types
1. Primary lactose intolerance: This is where idustrialized and commercial dairy is uncommon.
2. Secondary lactose intolerance: Exposure to intestinal parasites and gastrointestinal diseases are present.
3. Congenital lactase deficiency: A genetic disorder which prevents enzymatic production of lactase and it can happen at birth.
Symptoms
The symptoms may begin about 30 minutes to 2 hours after eating or drinking foods that contain lactose. The symptoms depends on how much you intake, age, ethnicity, and digestion rate. Some common symptoms are stomach cramps, bloating, flatulence, and diarrhea.
Common Tests
The digestive tract
1. The Lactose Tolerance Test: Fasting and then drinking something that contains lactose. Several blood samples will be taken within a 2-hour period to measure glucose. If the sugar level is high then most likely you are lactose intolerant.
2. The Hydrogen Breath Test: It measures hydrogen in a person's breath. If there is little hydrogen it is easy to detect. In this test a person drinks a lactose filled drink and the breath is analyzed during regular breathing. A high amount of hydrogen indicates improper digestion of lactose. Things such as, food, medication, and cigarettes may alter the test results.
3. Stool Acidity Test: It is used for baby's and young children to measure acid in thier stool. Lactic acid, other fatty acids, and glucose will be presented in the sample. This indicates a sign of lactose in the colon.
Dairy product
Lactose Content
Yogurt, plain, low-fat, 240 mL
5 g
Milk, reduced fat, 240 mL
11 g
Swiss cheese, 28 g
1 g
Ice cream, 120 mL
6 g
Cottage cheese, 120 mL
2–3 g
The tabel above shows the levels of lactose in dairy products.
Table of Contents
Lactose Intolerance
By: Gabby Langston & Brittany HimmeLactose is the sugar found in milk and is in other dairy products. When you are lactose intolerant you cannot digest foods or drinks with lactose in them. Lactase is an enzyme needed for proper metabolization of lactose in human beings. The lactose disaccharide cannot be absorved through the intestinal wall into the bloodstream, so remains in the intestines. When the bacteria adapts to the undigested sugar they switch over to lactose metabolism and this creates gas and unpleasant abdominal symptoms. Lactase breaks down milk and sugar into two simpler forms of sugar called glucose and galactose, and they are absorbed into the bloodstream. Not all people that have symptoms are lactose intolerant.
Molecular Basis Description
The picture on the left explains how glucose and galactose link together. Lactase binds with water to create the linkage. Once it is combined with water the lactase enzymes then move onto the next lactose molecule and this is repeated each time. The body does not need to produce many enzymes because they work efficiently and economically. They do not change after the reaction, they just move to the next lactose molecule. The outcome of this reaction is the formation of glucose and galactose. These monosaccharides are absorbed and ready to be transported in the small intestine.Major Types
1. Primary lactose intolerance: This is where idustrialized and commercial dairy is uncommon.2. Secondary lactose intolerance: Exposure to intestinal parasites and gastrointestinal diseases are present.
3. Congenital lactase deficiency: A genetic disorder which prevents enzymatic production of lactase and it can happen at birth.
Symptoms
The symptoms may begin about 30 minutes to 2 hours after eating or drinking foods that contain lactose. The symptoms depends on how much you intake, age, ethnicity, and digestion rate. Some common symptoms are stomach cramps, bloating, flatulence, and diarrhea.Common Tests
2. The Hydrogen Breath Test: It measures hydrogen in a person's breath. If there is little hydrogen it is easy to detect. In this test a person drinks a lactose filled drink and the breath is analyzed during regular breathing. A high amount of hydrogen indicates improper digestion of lactose. Things such as, food, medication, and cigarettes may alter the test results.
3. Stool Acidity Test: It is used for baby's and young children to measure acid in thier stool. Lactic acid, other fatty acids, and glucose will be presented in the sample. This indicates a sign of lactose in the colon.
References:
http://www.foodreactions.org/products/li.html
http://en.wikipedia.org/wiki/Lactose_intolerance
http://www.nlm.nih.gov/medlineplus/lactoseintolerance.html
Pictures:
http://oregonstate.edu/dept/foodsci/dairy/dairy_products.jpg
http://digestive.niddk.nih.gov/ddiseases/pubs/lactoseintolerance/#whatis